[libvirt] Need to re-work final "peer address" patches and re-push them

[Jiri Denemark]

On Thu, May 12, 2016 at 10:31:34 +0200, Andrea Bolognani wrote:
> On Thu, 2016-05-12 at 09:58 +0200, Jiri Denemark wrote:
> > On Wed, May 11, 2016 at 11:57:36 -0400, Laine Stump wrote:
> > > 
> > > I reverted these three patches that introduced and enabled a "peer" 
> > > attribute for type='ethernet' interface <ip> elements prior to the 
> > > release of 1.3.4 with the intent of fixing/re-posting them after 
> > > release, but forgot until today:
> > > 
> > > https://www.redhat.com/archives/libvir-list/2016-April/msg01995.html
> > > 
> > > I have patches for most of the bugs, but the one problem that still 
> > > doesn't have resolution is the naming of the "peer" attribute. In my 
> > > opinion, having the two address attributes named "address" and "peer" 
> > > makes it ambiguous which address is for the guest side and which for the 
> > > host side (especially since the attribute that has been named "peer" 
> > > would be set to the "address" in the netlink command, and the attribute 
> > > named "address" would be set to "peer" in the netlink command :-O).
> > > 
> > > Since "address" is an existing attribute, and already used for the guest 
> > > side IP address in lxc type='bridge' interfaces, it must remain as-is. 
> > > In order to make it obvious that the new address is for the host side of 
> > > the tap (or veth pair in the case of lxc), I propose calling it either 
> > > "host", or "hostAddress", e.g:
> > > 
> > >       <ip address='192.168.123.43' host='192.168.123.1' prefix='25'/>
> > > 
> > > or
> > > 
> > >       <ip address='192.168.123.4' hostAddress='192.168.123.1' prefix='25'/>
> > 
> > IMO "host" is better. After all it's an attribute of "ip" element so
> > it's obvious we're talking about addresses here.
> 
> I like "hostAddress" better myself :)
> 
> Is there any real chance the "prefix" attribute will need to be specified
> for the host as well? Because in that case we would clearly have to go
> with "hostPrefix", and using "host" instead of "hostAddress" would look
> quite ugly.

If there's any chance we'll need to get more data for the host side of
the interface (that's not the case for prefix, though), we should rather
use a subelement, something like

    <ip address='192.168.123.4' prefix='25'>
        <host address='192.168.123.1' .../>
    </ip>

Jirka